Image Resizer – Compress an Image to an Exact KB Size or Dimensions
Resize or compress an image to an exact size
Drop in a photo and set a target — an exact size in KB for a form upload, exact pixel dimensions, or lossless compression that only strips hidden metadata. JPG, PNG, WebP and iPhone HEIC.
- 1Add imagesOne or many
- 2Set a targetKB, or pixels
- 3DownloadResized on your device
Runs entirely in your browser — no upload, no sign-up.
About Image Resizer
Drop in one photo or a batch, choose a target — a maximum file size in kilobytes, or a width, height or percentage — and download the resized copies. Everything is processed in your browser, so the originals never leave your device.
Online forms, job portals and exam applications almost always cap the photo or document you upload: “image must be less than 20 KB”, “signature between 10 and 20 KB”, “photo up to 200 KB”. This tool works backwards from that number — it tries progressively lower JPEG quality, and shrinks the pixels if it has to, until the file fits the limit you set, then shows you exactly what size it landed on.
The Dimensions tab does the more familiar job: scale a photo to a maximum width or height, fit it inside a box, or reduce it by a percentage — keeping the aspect ratio and never enlarging past the original. Output can stay in the same format or convert to JPG, WebP or PNG.
Because it runs entirely on your device using the browser's canvas, there is no upload, no queue and no watermark, and it works the same on a phone as on a laptop. iPhone HEIC photos are decoded locally so you can resize them without converting first.
Which tab to use
Use Target file size when a form demands a number — 'under 50 KB', 'between 10 and 20 KB'. Use Dimensions when you need a size in pixels — a thumbnail, a profile picture, a banner. Use Lossless when you want a smaller file without changing a single pixel: it strips hidden metadata such as the embedded EXIF thumbnail, location data and software comments from JPEG and PNG files, which can save a surprising amount on phone photos. It will not shrink an image that carries none.
They solve different problems. Target file size trades quality for size, Dimensions changes how big the picture is, and Lossless changes neither.
Getting an exact pixel size
The Dimensions tab has two modes that sound alike. Fit inside keeps the aspect ratio: a 4:3 photo asked to fit 1000 × 1000 comes out 1000 × 750. Exact size crops to fill: the photo is scaled to cover the target and the overflow is trimmed from the centre, so asking for 1920 × 1080 always returns precisely that, never a stretched picture. If a face is near an edge, crop the photo first so the trim does not cut into it.
Images are never enlarged beyond the original in Fit inside, so asking for a wider image than you have returns the original width. The exact-size mode is the exception: it always delivers the size you asked for.
Hitting a very small KB limit
Limits like 20 KB are reachable, but expect compression to be visible, and the result depends on the picture. A plain scanned signature on white compresses very small with little visible loss; a detailed photo may need its pixel dimensions reduced as well as its quality. The tool does this automatically — it lowers JPEG quality first, then shrinks the pixels if it must, and shows the size it reached. If you need a larger image than a small target allows, raise the limit rather than the quality.
Sizes use 1 KB = 1,000 bytes, matching most upload forms, so a result under 50 KB is under the limit however the form counts.
Format, transparency and phone photos
JPEG has no transparency, so the see-through areas of a PNG saved as JPEG are lost and can turn black. Keep PNG if the transparent area matters. WebP is smaller than JPEG at similar quality but some older upload forms reject it, so choose JPG when a form lists only 'JPG or JPEG'. iPhone HEIC photos are decoded on your device, so they can be resized and saved as JPG without a separate conversion step.
Batches are limited to 30 images, processed one after another so the tab stays responsive. If one file cannot be read, it is reported rather than silently dropped.
What you can use it for
- Shrink a photo to the exact KB limit an exam or government form allows before uploading.
- Resize a scanned signature to fit a “signature must be 10–20 KB” rule.
- Make a photo small enough to attach to an email or a messaging app.
- Batch-resize product or blog images to a consistent maximum width.
- Convert and resize an iPhone HEIC photo to a JPG a website will accept.
How it works, step by step
- 1
Add your images
Drag in or choose up to 30 images — JPG, PNG, WebP or HEIC.
- 2
Pick a target
Choose a maximum file size in KB on the Target file size tab, or a width, height or percentage on the Dimensions tab.
- 3
Resize
Each image is processed on your device. The result shows the new size, dimensions and the quality it used.
- 4
Download
Save each resized image, or use Download all for the whole batch.
Frequently asked questions
Are my images uploaded to a server?
No. Decoding, resizing and re-encoding all happen in your browser with the canvas API. The files never leave your device and nothing is stored.
How does resizing to an exact KB size work?
For a target size the tool encodes the image as JPEG (or WebP) and searches for the highest quality that still fits under your limit. If the photo is too detailed to fit at full resolution, it reduces the pixel dimensions and tries again, then tells you the final size.
Will the image lose quality?
Hitting a small target like 20 KB from a multi-megapixel photo means real compression, so some softness is expected. Larger targets such as 200 KB or 1 MB usually look identical. The Dimensions tab, which only scales pixels, keeps quality high.
Can it resize iPhone HEIC photos?
Yes. HEIC and HEIF files are decoded locally in your browser and can be resized and saved as JPG, WebP or PNG.
Does it enlarge small images?
No. Images are only ever scaled down. Asking for a width larger than the original just keeps the original width.
How many images can I resize at once?
Up to 30 per batch. They are processed one after another so a large batch will not freeze the tab.